An increasing number of liquid crystal displays, especially, color liquid crystal displays with a TN (Twisted Nematic) liquid crystal display panel (TN-mode liquid crystal panel, TN panel) are being used in recent years in what has been traditionally the fields for CRTs (cathode ray tubes).
For example, Patent Document 1 discloses a liquid crystal display switching between TN panel driving methods according to whether the display image is a moving image or a still image.
These TN panels have some problems associated with viewing angle characteristics when compared to CRTs.
Grayscale characteristics change with an increasing line-of-sight angle (angle at which the panel is viewed; angle between the normal to the panel and the direction in which the panel is viewed). At some angles, grayscale inversion may occur.
Techniques have been accordingly developed which improve viewing angle characteristics using an optical film and also which mitigate grayscale inversion by modifying a display method. For example, Patent Documents 2 and 3 disclose a method whereby each frame is divided to write a signal to one pixel more than once and another in which signal write voltage levels are combined for improvement.
The viewing angle of TVs (television receivers) and other liquid crystal display panels which require wide viewing angles is increased by using liquid crystal of IPS (In-plane Switching) mode, VA (Vertical Alignment) mode, or like mode, instead of TN mode. For example, a VA-mode liquid crystal panel (VA panel) shows a contrast of 10 or greater within 170° up/down/left/right and is free from grayscale inversion.
Patent Document 1: Japanese Unexamined Patent Publication (Tokukai) 2001-296841 (published Oct. 26, 2001)
Patent Document 2: Japanese Unexamined Patent Publication 5-68221/1993 (Tokukaihei 5-68221; published Mar. 19, 1993)
Patent Document 3: Japanese Unexamined Patent Publication (Tokukai) 2002-23707 (published Jan. 25, 2002)
Non-patent Document 1: New Handbook for Color Science, Second Edition (Tokyo University Press; published Jun. 10, 1998)